Medical washers are conventionally known and are used to clean articles (e.g., medical devices, such as medical instruments and equipment) that have been exposed to bio-contaminants. Such washers typically clean the articles to remove bio-contaminants by directing jets or streams of fluid at the articles from spray heads or nozzles located within the washer. A typical cleaning operation may include a preliminary rinse cycle, a pre-wash cycle, a wash cycle, a post-wash rinse cycle, a thermal rinse cycle and a drying cycle. During the rinse and wash cycles the articles are exposed to one or more chemical cleaning and rinsing solutions.
It is not unusual for a cleaning operation to be followed by a visual inspection conducted by a human to insure that there are no residual bio-contaminants (hereinafter referred to as “soil”) on the articles. The soil may include organic residues including, but not limited to, blood, fat, mucous, lipids, carbohydrates, bone, hair, protein, and food product. Some articles have unique shapes, corners or crevices that make removal of the bio-contaminants therefrom difficult. Human visual inspection helps ensure that post-wash articles with soil thereon are not allowed to proceed to further processing (e.g., sterilization) without first removing any remaining bio-contaminants.
As will be appreciated, a human visual inspection is both time-consuming and costly. Moreover, it is difficult to detect minute amounts of soil by human visual inspection, and such visual inspection is subject to human error (for example, person-to-person variations and individual biases). Furthermore, it is observed that human visual inspection is a binary qualitative process, not quantitative.
Medical washing is only one example of a field in which there is a need for decontamination and inspection procedures. Similar decontamination and inspection procedures are performed in other, different fields of endeavor, including fields in which industrial processing equipment is exposed to organic residues. Such fields include the agrifood sector, such as dairy, brewery, and other food processing facilities.
Some prior art methods for optical detection of soil use a fluorescent dye or agent to detect the presence of soil on an article. In such systems, the fluorescent agent is applied to the article, for example, by exposing the article to a solution that includes the fluorescent agent. The fluorescent agent binds to organic residues (e.g., proteins), and thus affixes to the soil to label the bio-contaminant. Where there is no soil on the article, the fluorescent agent does not become affixed thereto, and thus can be washed off. To provide optical detection of the soil according to certain prior art methods, the article can be exposed to “black light” (i.e., electromagnetic radiation in the ultraviolet range having wavelengths around 315-400 nm), which is absorbed by the fluorescent agent. Absorbance of this ultraviolet (UV) light causes the fluorescent agent to emit visible light (i.e., to be fluorescent), thereby identifying the presence of soil to a human inspector. A typical human eye is responsive to light in the wavelength range of 390-750 nm. A fluorophore such as fluorescein has an excitation under light having a wavelength of about 488-490 nm, upon which the fluorescein emits light (i.e., fluoresces) at a wavelength of about 513 nm.
This prior art method does not allow personnel to carry out their task of reprocessing of articles in desirable ambient light conditions, and thus makes it difficult for personnel to disassemble, reassemble, and inspect articles for cleanliness. Recommended illuminance levels for such work environments can range from 200 lux to 2000 lux, and more typically range from 1400 lux to 2000 lux.
It is becoming increasingly common to utilize cannulated or lumened devices within the surgical operating room. It is understood in the art that a “lumen” is a cavity within the interior space of a tubular passageway or structure. There are a wide variety of lumened instruments in use today. The cost of instruments such as endoscopes is often very high, and so thorough reprocessing is becoming increasingly desirable.
One significant challenge is the detection of any residual soil remaining inside the inner portion of a lumen after manual cleaning of the interior of the lumen by use of a brush or a swab. Prior art approaches to confirming cleanliness are labor-intensive and thus very expensive while not very precise. Visual inspection is only qualitative and the detection and/or integrity of cleanliness validation is dependent on human error.
The present invention provides a method and apparatus for optical detection of soil in a lumen of a medical instrument, such as an endoscope.
The present invention also provides a method and apparatus for optical inspection of other types of lumened and cannulated structures, such as small pipes and tubes included in industrial applications such as agrifood (dairy, brewery, and other food processing facilities).